Where do you have your receiver placed that you can only reach two seating positions? The advantage of Audyssey is that it can optimize for multiple seating positions. I found it very good for setting trim levels and speaker distances.
With the radio shack meter, you set it on C weighting and play test tones through your speakers. The receiver should have a pink noise (a wide band of frequencies) generator that sends the same signal through alternating speakers on a set pattern so that you can compare the sound level of each.
A tripod is handy for holding the meter steady.
